Preliminary Evaluation of Point-injection for Application of P & K to Forage Grasses in Southern Alberta

Description
Improved fertilizer use efficiency has been observed in corn and wheat when fertilizer is applied by point-injection. Because point-injection places fertilizer directly into the rooting zone with minimal crop and soil zone disturbance, it may be ideal for fertilizer placement in perennial forages. This greenhouse study is determining the benefits of point-injection for improving P and K use by forage grass. Results will be sued to determine the justification and design of future large-scale field experiments.


Justification
The productivity of perennial forage grasses is often curtailed after several years growth by deficiencies of phosphorus and potassium. Nitrogen, which is comparatively mobile in the soil, can be readily applied to existing forage stands by top-dressing. Because k and especially P are not readily leached into the soil profile, however, top-dressed applications of these nutrients may not exhibit acceptable efficiency in deficiency correction.

Point-injection is a relatively new method of fertilizer application that utilizes a spoked wheel to penetrate the soil surface and introduce fertilizer into the rooting zone without disruption of the crop. This method may permit improvement of P and K fertilizer-use efficiency in forages by enhancing immediate accessibility of the nutrients by the crop.

The proposed research would supplement an existing large-scale field project which seeks to determine the feasibility of point-injection for the enhancement of fertilizer efficiency in winter wheat, spring cereals, and alfalfa. If successful, the proposed research would provide detailed information regarding P and k uptake as a function of placement under controlled conditions, and determine whether large-scale field evaluations are warranted.


Objectives
To determine the potential benefits of point-injection for the enhancement of fertilizer P and K use by forage grasses.